This is the filming location of Sam's house in Sleepless in Seattle, and is one of many floating homes on Lake Union (there are SO many that there are realtors dedicated entirely to floating homes, barges, and houseboats!). The downside? This famous address is ONLY visible from the lake. The upside? You can always rent a peddle boat from the Center for Wooden Boats and (kind of) reenact another famous movie scene on Lake Union from 10 Things I Hate About You.
2640 Westlake Ave N, Seattle, WA 98109, USA